Stool



FIG. 1 is a perspective view of a stool in accordance with the present invention;

FIG. 2 is a left side view thereof;

FIG. 3 is a rear side view thereof;

FIG. 4 is a right side view thereof;

FIG. 5 is a front side view thereof;

FIG. 6 is a top side view thereof; and,

FIG. 7 is a bottom side view thereof.

The broken lines form no part of the claimed design. 

The ornamental design for a stool, as shown and described. 